This invention relates to "natural air" drying systems for grain storage bins wherein proper amounts of moisture laden air are metered back into the drying air stream, after having passed through the bin, to mix with atmospheric air being supplied as drying air, and prevent overdrying of the grain.
Various prior art systems for recycling humid air in such systems have been proposed, as exemplified in the following patents - however, the present system differs in its relative simplicity and practicality: U.S. Pat. Nos. 1,534,499; 4,077,134; 2,318,027; 4,263,722; 3,380,174; 4,268,971.